Min Kyoungin, Cho Minseon, Han Se-Young, Shim Yoon-Bo, Ku Jakang, Ban Changill
Department of Chemistry, Pohang University of Science and Technology, San31, Hyojadong, Pohang, Gyeongbuk 790-784, South Korea.
Biosens Bioelectron. 2008 Jul 15;23(12):1819-24. doi: 10.1016/j.bios.2008.02.021. Epub 2008 Mar 2.
Tuberculosis is the most frequent cause of infection-related death worldwide. We constructed a simple and direct electrochemical sensor to detect interferon (IFN)-gamma, a selective marker for tuberculosis pleurisy, using its RNA and DNA aptamers. IFN-gamma was detected by its 5'-thiol-modified aptamer probe immobilized on the gold electrode. Interaction between IFN-gamma and the aptamer was recorded using electrochemical impedance spectroscopy and quartz crystal microbalance (QCM) with high sensitivity. The RNA-aptamer-based sensor showed a low detection limit of 100 fM, and the DNA-aptamer-based sensor detected IFN-gamma to 1 pM in sodium phosphate buffer. With QCM analysis, the aptamer immobilized on the electrode and IFN-gamma bound to the aptamer probe was quantified. This QCM result shows that IFN-gamma exists in multimeric forms to interact with the aptamers, and the RNA aptamer prefers the high multimeric state of IFN-gamma. Such a preference may describe the low detection limit of the RNA aptamer shown by impedance analysis. In addition, IFN-gamma was detected to 10 pM by the DNA aptamer in fetal bovine serum, a mimicked biological system, which has similar components to pleural fluid.
结核病是全球感染相关死亡的最常见原因。我们构建了一种简单直接的电化学传感器，利用干扰素（IFN）-γ的RNA和DNA适配体来检测IFN-γ，它是结核性胸膜炎的一种选择性标志物。通过固定在金电极上的5'-硫醇修饰的适配体探针检测IFN-γ。使用电化学阻抗谱和石英晶体微天平（QCM）以高灵敏度记录IFN-γ与适配体之间的相互作用。基于RNA适配体的传感器检测限低至100 fM，基于DNA适配体的传感器在磷酸钠缓冲液中可检测到1 pM的IFN-γ。通过QCM分析，对固定在电极上的适配体以及与适配体探针结合的IFN-γ进行了定量。该QCM结果表明，IFN-γ以多聚体形式存在以与适配体相互作用，并且RNA适配体更倾向于IFN-γ的高多聚体状态。这种偏好可能解释了阻抗分析显示的RNA适配体的低检测限。此外，在模拟生物系统胎牛血清中，DNA适配体可检测到10 pM的IFN-γ，胎牛血清的成分与胸水相似。
